Laser beam transmitter

ABSTRACT

A laser oscillator includes a light condensing block having a through-hole for housing a laser medium, and an aperture for introducing excitation light from an excitation light source module into the through-hole; an end plate fixed to an end of the light condensing block, in which a cooling water channel for leading cooling water to the light condensing block and a cooling water channel for leading cooling water to the excitation light source module are formed; and a flow tube fixed and sealed by the end plate, for forming a cooling water passage for the laser medium; and an excitation light source module in which a cooling water channel, communicating with the water channel for the excitation light source module in the end plate, is formed for cooling its excitation light source.

TECHNICAL FIELD

The present invention relates to a laser diode (hereinafter, referred toas an LD) excitation solid-state laser device that uses LDs asexcitation light sources, and to a light condensing module used for thedevice.

BACKGROUND ART

In a conventional LD-excitation solid-state laser device, a lightcondenser for confining the excitation light to the vicinity of thesolid-state laser medium, and a flow tube for water-cooling thesolid-state laser medium have been directly attached to side plates forsupporting the excitation unit. In addition, cooling systems for the LDsand for the solid-state laser medium have been independent, and coolingwater only for the solid-state laser medium has been supplied anddischarged through the side plates (see Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open No. 277837/2000 (FIG. 4)

Because the conventional LD-excitation solid-state laser device has beenconfigured so that the light condenser for confining excitation light tothe vicinity of the solid-state laser medium, and the flow tube forwater-cooling the solid-state laser medium are directly attached to theside plates for supporting the excitation unit, there has been a problemin that it is difficult to assemble the excitation unit accurately andeasily.

Moreover, cooling-water piping systems for cooling the LDs that areexcitation light sources and for cooling the solid-state laser mediumare independent. The cooling water for the solid-state laser medium issupplied and discharged through the side plates that support theexcitation units, while in order to cool the LDs, independent pipingmust be provided to supply and discharge cooling water. Therefore, therehas been a problem in that the conventional LD-excitation solid-statelaser device requires piping components in accordance with the pluralityof cooling systems, and consequently the number of components andassembly man-hours increase.

Furthermore, there has been another problem in that piping units forsupplying cooling water lead to water leakage, and to decline in thereliability of the LD-excitation solid-state laser device.

DISCLOSURE OF THE INVENTION

The present invention has been made to resolve such problems, and aimsto realize a light condensing module that is easy to assemble, and doesnot require piping for supplying cooling water for LD modules, and anLD-excitation solid-state laser device that incorporates the lightcondensing module.

In order to achieve the object, according to the first aspect, anLD-excitation solid-state laser device includes: a light condensingblock having a through-hole for housing a laser medium, and an aperturefor introducing excitation light from an excitation light source moduleinto the through-hole; an end plate fixed to an end of the lightcondensing block, in which a cooling water channel for leading coolingwater to the light condensing block and a cooling water channel forleading cooling water to the excitation light source module are formed;a flow tube, fixed and sealed by the end plate, for forming a coolingwater passage for the laser medium; and an excitation light sourcemodule in which a cooling water channel, communicating with the coolingwater channel for the excitation light source module in the end plate,is formed for cooling its excitation light source.

Moreover, the excitation light source module is fixed to the end platewith a fixing means.

Furthermore, supply of cooling water into the light condensing block isfed through a front face of the end plate into the flow tube, and supplyof cooling-water into the excitation light source module is fed bypassedfrom the front face of the end plate to the side face of the end plate.

Moreover, a cooling-water supplying inlet for allowing flow into thelight condensing block is provided in the end plate, to cool the lightcondensing block with cooling water from the end plate.

Furthermore, an LD-excitation solid-state laser device includes: a lightcondensing block having a through-hole for housing a solid-state lasermedium, and an aperture for introducing excitation light from anexcitation light source module into the through-hole; a water supplyingplate fixed to one end of the light condensing block, in which a coolingwater channel for leading cooling water to the light condensing blockand a cooling water channel for leading cooling water to the excitationlight source module are formed; a water discharging plate, fixed to theother end of the light condensing block, in which a water dischargingchannel for discharging cooling water that has cooled the lightcondensing block and a water discharging channel for discharging coolingwater that has cooled the excitation light source module are formed; aflow tube, fixed and sealed by the water supplying plate and the waterdischarging plate, for forming a cooling water passage for thesolid-state laser medium; an excitation light source module in which acooling water channel, communicating with the water channel for theexcitation light source module in the water supplying plate and with thewater channel for the excitation light source module in the waterdischarging plate, is formed for cooling its excitation light source;side plates, fixing both ends of the the light condensing block, inwhich a water supply coupling and a water discharge coupling for coolingwater each are provided; and solid-state laser medium fixing plugs forfixing both ends of the solid-state laser medium and sealing flowchannels for supplied/discharged cooling water, within spaces enclosedby the fixing plugs together with the side plates.

Moreover, one of the side plates is formed integrally with the watersupplying plate, and the other side plate is formed integrally with thewater discharging plate, and each of the solid-state laser medium fixingplugs, each side plate, and the light condensing block are fastened by asingle fastening means.

Furthermore, a ceramic is used as a diffusely reflecting material forthe light condensing block.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a light condensing module inEmbodiment 1 of the invention.

FIG. 2 is a perspective view illustrating a detailed structure of alight condensing block in Embodiment 1 of the invention.

FIG. 3 is a perspective view illustrating a method of fixing an LDmodule, which is an excitation light source, to the light condensingmodule in Embodiment 1 of the invention.

FIG. 4 is a cross-sectional schematic diagram illustrating a structureof an LD-excitation solid-state laser device using the light condensingmodule and the LD modules in Embodiment 1 of the invention.

FIG. 5 is a cross-sectional schematic diagram illustrating a structureof an LD-excitation solid-state laser device in Embodiment 2 of theinvention.

FIG. 6 is a cross-sectional schematic diagram illustrating a structureof an LD-excitation solid-state laser device in Embodiment 3 of theinvention. It is a whole structural diagram illustrating aunit-information setting system using a unit device and a setting deviceaccording to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

FIG. 1 is a perspective view illustrating a light condensing module inEmbodiment 1 of the invention.

In FIG. 1, a light condensing block 1 having a form of a quadratic prismis configured with a diffusely reflecting material composed of aceramic. Slit apertures 102 are provided on four side faces of the lightcondensing block 1.

A rod water-supplying inlet 201 and LD water-supplying inlets 202 areprovided in the central portion of a water supplying plate 2 fixed toone end of the light condensing block 1, and an LD cooling-water outlet203 is provided in each of the side faces thereof. Flow channels areformed within the water supplying plate 2 so that the LD water-supplyinginlets 202 and the LD cooling-water outlets 203 are connected. Inaddition, in the water supplying plate 2, LD fixing screw holes 204 forfixing LD modules, which are excitation light sources, light-condenserfixing holes 205 for fixing the light condensing block 1 to the watersupplying plate 2, and side-plate fixing holes 206 for combining with awater supplying/discharging side plate are formed.

Numeral 3 denotes a water discharging plate fixed to the other end ofthe light condensing block 1, having a form and a structure symmetricalto the water supplying plate 2. In the water discharging plate, rodwater-discharging outlets 301 corresponding to the rod water-supplyinginlets 201 in the water supplying plate 2, and LD water-dischargingoutlets 302 corresponding to the LD water-supplying inlets 202 areformed. LD cooling-water inlets 303 are provided on the side faces ofthe water discharging plate 3, and LD fixing screw holes 304 andlight-condenser fixing holes 305 are formed in the water dischargingplate 3.

FIG. 2 is a perspective view illustrating a detailed structure of thelight condensing block 1 used in the light condensing module illustratedin Embodiment 1 of the invention. In FIG. 2, numeral 101 denotes athrough-hole that penetrates through the center of the light condensingblock 1, and slit apertures 102 provided in the side faces of the lightcondensing block 1 are formed so as to reach the through-hole 101.Numeral 103 denotes water-supplying-plate fixing screw holes formed inone end of the light condensing block, for fixing the water supplyingplate 2. In the other end of the light condensing block 1,water-discharging-plate fixing screw holes for fixing the waterdischarging plate 3 are formed. The screw holes correspond tolight-condenser fixing holes 205 and 305, respectively.

Numeral 4 denotes a flow tube installed within the through-hole 101 ofthe light condensing block 1. The flow tube is composed of a materialtransparent with respect to the wavelength of the LDs used as excitationlight sources. In the present embodiment, quartz is used as a materialof the flow tube 4. Moreover, both ends of the flow tube 4 are sealedand fixed by the water supplying plate 2 and the water discharging plate3.

FIG. 3 is a perspective view illustrating a method of fixing an LDmodule, which is an excitation light source, to the light condensingmodule illustrated in FIG. 1. In FIG. 3, in the LD module 5, which is anexcitation light source, a plurality of (six in the embodiment) LDpackages 501 configured by coupling LD bars, which are light emittingunit main bodies, is fixed in parallel on a water-cooling heat sink. Thewater-cooling heat sink in the LD package 5 is supplied with coolingwater from a manifold 502. Moreover, LD fixing holes 503 for fixing theLD module 5 to the light condensing module 1 are formed in the manifold502, which is fastened by LD fixing bolts 507 being screwed into an LDfixing screw hole 204 in the water supplying plate 2 and an LD fixingscrew hole 304 in the water discharging plate 3. At this time, the lightemitting unit in the LD module 5 and the slit aperture 102 in the lightcondensing block 1 are positioned so as to face each other, andexcitation light emitted from the LD module 5 passes through the slitaperture 102 into the through-hole 101 in the light condensing block 1illustrated in FIG. 2.

Furthermore, flow channels of cooling water are formed within themanifold 502 in the LD module 5, and cooling water is channeled from theLD cooling-water outlet 203 in the water supplying plate 2 through theflow channel within the manifold to the water-cooling heat sink in theLD package 501. Then, the cooling water that has cooled the LD package501 is discharged through the flow channel within the manifold into theLD-cooling-water inlet 303 in the water discharging plate 3.

In addition, although a method of fixing an LD module 5 to only one sideface of the light condensing module is illustrated in FIG. 3, other LDmodules 5 are also fixed to the remaining three side faces according tothe identical method.

FIG. 4 is a cross-sectional schematic diagram illustrating a structureof an LD-excitation solid-state laser device for exciting a solid-statelaser medium, including the light condensing module and the LD modulesillustrated in FIG. 1 through FIG. 3. In the embodiment, YAG (yttriumaluminium garnet) crystal doped by Nd (neodymium) as an activatingmedium is used for a rod-type solid-state laser medium 6. Rod fixingplugs 7 for sealing cooling water fix both ends of the solid-state lasermedium 6. A water-supplying side plate 8 is provided to support one endof the light condensing module, and to supply cooling water into thelight condensing module. A water-supplying flow channel 801 forsupplying cooling water is formed within the water-supplying side plate,and a water supply coupling 802 is provided at a water-supplying channelinlet on the side face of the water-supplying side plate 8. Awater-discharging side plate 9 is provided to support the other end ofthe light condensing module, and to discharge cooling water. Awater-discharging flow channel 901 for discharging cooling water isformed within the water-discharging side plate, and a water dischargecoupling 902 is provided at a water-discharging channel outlet on theside face of the water-discharging side plate 9. In addition, numeral504 denotes cooling-water flowpaths schematically illustrated in dashedline, which is formed within the LD package 501 illustrated also indashed line. A cooling-water supplying channel 505 and a cooling-waterdischarging channel 506 are formed within the manifold 502.

In FIG. 4, flows of cooling water in the LD-excitation solid-state laserdevice are illustrated with arrows for explanation. The cooling watersupplied from the water supply coupling 802 in the water-supplying sideplate 8 flows through the water supplying channel 801 up to the watersupplying plate 2 at the end of the light condensing module. The coolingwater that has reached the water supplying plate 2 is distributed to therod water-supplying inlet 201 and the LD water-supplying inlet 202. Thecooling water that has flowed into the rod water-supplying inlet 201flows through the gap between the outer face of the solid-state lasermedium 6 and the flow tube 4 up to the water discharging plate 3 at theother end of the light condensing module, while cooling the solid-statelaser medium 6, and then is discharged from the rod water-dischargingoutlet 301 to the outside of the light condensing module. Meanwhile, thecooling water that has flowed into the LD water-supplying inlet issupplied from the LD cooling-water outlet 203 to the cooling-watersupplying channel 505 formed within the manifold 502 in the LD module 5.The cooling water in the cooling-water supplying channel 505 isdischarged through the cooling-water flow channel 504 within the heatsink in the LD package 501 into the cooling-water discharging channel506. Here, the LD package 501 is effectively cooled, when the coolingwater passes through the cooling-water flow channel 504. After that, thecooling water discharged to the cooling-water discharging channel 506flows into the cooling-water inlet 303 provided in the water dischargingplate 3 of the light condensing module, and then is discharged from theLD water-discharging outlet 302 in the water discharging plate 3 to theoutside of the light condensing module. The cooling water that hascooled the LD module 5 and the solid-state laser medium 6 and that hasbeen discharged to the outside of the light condensing module flowsthrough the water-discharging flow channel 901 in the water-dischargingside plate 9, and is discharged from the water discharge coupling 902 tothe outside of the LD-excitation solid-state laser device.

Meanwhile, the excitation light emitted from the LD module 5 passesthrough the slit aperture 102 provided on the side face of the lightcondensing block 1 into the through-hole 101 in the light condensingblock 1, and excites the solid-state laser medium 6 via the flow tube 4and the cooling water. Inverted distribution corresponding to laserlevels is formed within the excited solid-state laser medium 6, and alaser beam can be taken out from the excited solid-state laser medium 6by disposing at both ends of the solid-state laser medium 6 lightresonators composed of a total reflection mirror and a partialreflection mirror. In addition, because the excitation light emittedfrom the LD module 5 is effectively confined within the through-hole 101of the light condensing block 1, most of the excitation light isabsorbed in the solid-state laser medium 6 so that the solid-state lasermedium 6 can be efficiently excited. In the embodiment, because aceramic, which is a diffusely reflecting material, is used as a materialfor the light condensing block 1, it becomes easy to uniformly excitethe solid-state laser medium 6 to efficiently generate ahighly-concentrated laser beam.

In the light condensing module described in the embodiment, the slitapertures 102 for introducing excitation light into the through-hole 101of the light condensing block are provided on the side faces of thelight condensing block 1, the water supplying plate 2 and the waterdischarging plate 3 are disposed at both ends of the light condensingblock 1, and the means for fixing LD modules 5 are provided in the sidefaces of the water supplying plate 2 and the water discharging plate 3,whereby the light emitting units in the LD modules 5, which areexcitation light sources, can be disposed easily and accurately withrespect to the slit apertures 102 of the light condensing block 1,excitation light can be efficiently introduced into the through-hole 101of the light condensing block 1, and consequently the solid-state lasermedium 6 can be efficiently and uniformly excited, so that ahighly-concentrated laser beam can be stably generated.

In addition, the LD water-supplying inlet 202 and the LDwater-discharging outlet 302 are provided on the front faces of thewater supplying plate 2 and the water discharging plate 3, the LDcooling-water outlets 203 communicating with the LD water-supplyinginlets are provided on the side faces of the water supplying plate 2,and the LD cooling-water inlets 303 communicating with the LDwater-discharging outlets 302 are provided on the side faces of thewater discharging plate 3, whereby the light condensing module isconfigured so that cooling water is directly supplied and dischargedthrough the LD cooling-water outlets 203 and the LD cooling-water inlets303 to the manifolds 502 in the LD modules 5, and consequently, coolingwater can be supplied and discharged to the LD module with a simpleconfiguration. Moreover, because it is not necessary to provide specialpiping or the like for supplying cooling water to and discharging itfrom the LD module, the number of components of the LD-excitationsolid-state laser device and assembly man-hours thereof are reduced, andreduction in manufacturing costs can be achieved. Furthermore, becausepiping or the like for supplying cooling water to the LD module 5 is notrequired, the reliability with respect to leakage of cooling water canalso be enhanced. In addition, because pressure loss across the waterchannel when supplying cooling water to the LD module is reduced,performance requirements to a pump for supplying cooling water arereduced, so that downsizing of a cooling-water supplier and reduction inmanufacturing costs can be achieved.

Furthermore, if an LD-excitation solid-state laser device is configuredso that one end of the light condensing module is supported by thewater-supplying side plate 8, within which the water-supplying flowchannel 801 is provided, the other end thereof is supported by thewater-discharging side plate 9, within which the water-discharging flowchannel 901 is provided, and the solid-state laser medium 6 is fixed andsealed to the water-supplying side plate 8 and the water-dischargingside plate 9 using the rod fixing plugs 7; and if cooling water issupplied and discharged with respect to the solid-state laser medium 6and the LD modules 5 through the water-supplying flow channel 801 of thewater-supplying side plate 8 and the water-discharging flow channel 901of the water-discharging side plate 9; then, without dividing thecooling system for supplying water from outside to the LD-excitationsolid-state laser device into a cooling system for the solid-state lasermedium 6 and a cooling system for the LD modules, only a single systemcan supply and discharge cooling water to the both; whereby theconfiguration of the laser cooling system using the LD-excitationsolid-state laser device can be simplified, reduction in manufacturingcosts can be achieved and the reliability can be enhanced.

Moreover, it would be obvious that the flow volumes of cooling-water tothe solid-state laser medium 6 and the LD modules 5 can be adjusted todesired flow volumes for distribution, in accordance withcross-sectional areas of the flow channels related to cooling-watersupply and discharge, including the rod water-supplying inlet 201 andthe rod water-discharging outlet 301 provided in the water supplyingplate 2 and the water discharging plate 3, the LD water-supplying inlets202 and the LD water-discharging outlets 302, and the cooling-watersupplying channels 505 and the water discharging channels 506 within themanifolds 502 in the LD modules 5.

Embodiment 2

FIG. 5 is a cross-sectional schematic diagram illustrating a structureof an LD-excitation solid-state laser device in Embodiment 2 of theinvention. A light condensing module and an LD-excitation solid-statelaser device according to the present embodiment have configurationssimilar to those in the LD-excitation solid-state laser device inEmbodiment 1, illustrated in FIG. 4. In addition to that, alight-condensing-block water-supplying inlet 205 is provided in thewater supplying plate 2, and a light-condensing-block water-dischargingoutlet 306 is provided in the water discharging plate 3; and alight-condenser cooling-water flow channel 104, which is a through-hole,is provided in the light condensing block 1 at a position correspondingto the light-condensing-block water-supplying inlet 205 in the watersupplying plate 2, and to the light-condensing-block water-dischargingoutlet 306 in the water discharging plate 3. In the embodiment, coolingwater is supplied and discharged, through the water supplying plate 2and the water discharging plate 3, with respect to the light condensingblock 1, together with the solid-state laser medium 6 and the LD modules5, to perform water-cooling of the light condensing block 1.

In the light condensing module according to the embodiment, not only thesame effects as in the light condensing module in Embodiment 1 can beachieved, but also, because the light condensing block 1 can bewater-cooled, heat generation from the light condensing block 1 due toabsorption of excitation light can be effectively suppressed, andthermal deformation of the light condensing block can be suppressed, sothat the solid-state laser medium can be stably excited at all times.Moreover, because heat generation from the light condensing block 1 canbe effectively suppressed, thermal deformation can be suppressed,reflectance of the inner face of the through-hole 101 in the lightcondensing block 1 can be prevented from deteriorating, and a highconfining effect of excitation light can be maintained at all times, sothat the solid-state laser medium 6 can be efficiently excited; wherebythe reliability of the LD-excitation solid-state laser device can beenhanced.

Furthermore, because cooling water for the light condensing block 1 isalso supplied and discharged through the water supplying plate 2 and thewater discharging plate 3, it is not necessary to provide piping or thelike separately for water-cooling of the light condensing block 1,reliability with respect to leakage of water is enhanced, and the numberof components and man-hours can be reduced, so that reduction inmanufacturing costs can be achieved.

Embodiment 3

FIG. 6 is a cross-sectional schematic diagram illustrating a structureof an LD-excitation solid-state laser device in Embodiment 3 of theinvention. In the present embodiment, the LD-excitation solid-statelaser device has a configuration in which the water supplying plate 2serves also as the water-supplying side plate 8, and the waterdischarging plate 3 serves also as the water-discharging side plate 9.The configuration is similar to that in Embodiment 2. As described inthe present embodiment, with the configuration in which the watersupplying plate 2 serves also as the water-supplying side plate 8, andthe water discharging plate 3 serves also as the water-discharging sideplate 9, not only the same effects as in Embodiment 2 described abovecan be achieved, but also further reduction of the number of componentsand assembly man-hours is made possible, so that reduction in themanufacturing costs can be achieved. In addition, an installationaccuracy of the solid-state laser medium 6 with respect to the lightcondensing module is enhanced, and the risk of water leakage at thejoint between the water supplying plate 2 and the water-supplying sideplate 8, and at the joint between the water discharging plate 3 and thewater-discharging side plate 9 is eliminated, whereby the reliability ofthe LD-excitation solid-state laser device can be further enhanced.

Moreover, although, in the embodiments described above, theconfigurations for exciting the solid-state laser medium 6, in which thelight condensing block 1 having a form of a quadratic prism is used, andthe LD modules 5 are disposed on the four side faces of the lightcondensing block 1, have been described, the form of the lightcondensing block and the number of LD modules are not limited to those.For example, in a case in which eight LD modules are used, if a lightcondensing block having a form of an octagonal prism is used, and the LDmodules are disposed on eight side faces of the light condensing block,then, not only the same effects as in the above-described embodimentscan be achieved, but also the solid-state laser medium can be excited toa high density so that the laser beam can be further efficiently takenout, and the output power can be effectively increased with the simpleand compact configuration being maintained. Furthermore, if an oddnumber of LD modules and a light condensing block having a form of anodd-number-polygonal prism are used, irradiating light from the LDmodule disposed facing across the light condensing block can be avoided,and the reliability of LD modules can be enhanced.

Moreover, in the embodiments described above, the configurations inwhich a rod-type YAG crystal is used for a solid-state laser medium havebeen described. However, it would be obvious that the kind and the formof solid-state laser media are not limited to those, but a slab-typesolid-state laser medium, for example, can also be used to achievesimilar effects.

Furthermore, in the embodiments described above, the configurationshaving a cylindrical through-hole at the center of the light condensingblock have been described. However, as long as excitation light can beeffectively confined, the form of the through-hole is not limited tothat.

INDUSTRIAL APPLICABILITY

As described above, the invention is suitable to be used for a laseroscillator including an LD-excitation solid-state laser device in whichlaser diodes are used as excitation light sources.

1-7. (canceled)
 8. A laser oscillator comprising: an excitation lightsource module in which a cooling water channel for cooling itsexcitation light source is formed; a light condensing block having athrough-hole for housing a laser medium, and an aperture for introducinginto the through-hole excitation light from the excitation light sourcemodule; an end plate fixed to an end of the light condensing block, inwhich a cooling water channel for leading cooling water to the lightcondensing block and a cooling water channel for leading cooling waterto the excitation light source module are formed; and a flow tube, fixedand sealed by the end plate, for forming a cooling water passage for thelaser medium; wherein an aperture of the cooling water channel on theexcitation- light- source-module side of the end plate, communicatingwith the cooling water channel formed in the excitation light sourcemodule, is provided on a side face of the end plate.
 9. A laseroscillator according to claim 8, wherein the excitation light sourcemodule is fixed to the end plate with a fixing means.
 10. A laseroscillator according to claim 9, wherein supply of cooling water intothe light condensing block is fed through a front face of the end plateinto the flow tube, and supply of cooling-water into the excitationlight source module is fed bypassed from the front face of the end plateto the side face of the end plate.
 11. A laser oscillator according toclaim 8, wherein a cooling-water supplying inlet for allowing flow intothe light condensing block is provided in the end plate, to cool thelight condensing block with cooling water from the end plate.
 12. Alaser oscillator according to claim 9, wherein a cooling-water supplyinginlet for allowing flow into the light condensing block is provided inthe end plate, to cool the light condensing block with cooling waterfrom the end plate.
 13. A laser oscillator according to claim 10,wherein a cooling-water supplying inlet for allowing flow into the lightcondensing block is provided in the end plate, to cool the lightcondensing block with cooling water from the end plate.
 14. A laseroscillator comprising: an excitation light source module in which acooling water channel for cooling its excitation light source is formed;a light condensing block having a through-hole for housing a solid-statelaser medium, and an aperture for introducing into the through-holeexcitation light from the excitation light source module; a watersupplying plate fixed to one end of the light condensing block, in whicha water supplying channel for leading cooling water to the lightcondensing block and a water supplying channel for leading cooling waterto the excitation light source module are formed; a water dischargingplate, fixed to the other end of the light condensing block, in which awater discharging channel for discharging cooling water that has cooledthe light condensing block and a water discharging channel fordischarging cooling water that has cooled the excitation light sourcemodule are formed; a flow tube, fixed and sealed by the water supplyingplate and the water discharging plate, for forming a cooling waterpassage for the solid-state laser medium; side plates, fixing both endsof the light condensing block, in which a water supply coupling and awater discharge coupling for cooling water are provided, respectively;and solid-state laser medium fixing plugs for fixing both ends of thesolid-state laser medium and sealing flow channels forsupplied/discharged cooling water, within spaces enclosed by the fixingplugs together with the side plates; wherein an aperture of the watersupplying channel on the excitation-light -source-module side of thewater supplying plate, communicating with the cooling water channelformed in the excitation light source module, is provided on a side faceof the water supplying plate, and an aperture of the water dischargingchannel on the excitation -light -source -module side of the waterdischarging plate, communicating with the cooling water channel formedin the excitation light source module, is provided on a side face of thewater discharging plate.
 15. A laser oscillator according to claim 14,wherein one of the side plates is formed integrally with the watersupplying plate, and the other side plate is formed integrally with thewater discharging plate, and each of the solid-state laser medium fixingplugs, each side plate, and the light condensing block are fastened by asingle fastening means.
 16. A laser oscillator according to claim 8,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 17. A laser oscillator according to claim 9,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 18. A laser oscillator according to claim 10,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 19. A laser oscillator according to claim 11,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 20. A laser oscillator according to claim 12,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 21. A laser oscillator according to claim 13,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 22. A laser oscillator according to claim 14,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.
 23. A laser oscillator according to claim 15,wherein a ceramic is used as a diffusely reflecting material for thelight condensing block.